Add miscellaneous missing docs

doc/attr.xml

@@ -1117,6 +1117,7 @@ gap> DigraphUndirectedGirth(D);
 <#GAPDoc Label="ArticulationPoints">
 <ManSection>
   <Attr Name="ArticulationPoints" Arg="digraph"/>
+  <Attr Name="CutVertices" Arg="digraph"/>
   <Returns>A list of vertices.</Returns>
   <Description>
     A connected digraph is <E>biconnected</E> if it is still connected (in the
@@ -1143,6 +1144,9 @@ gap> DigraphUndirectedGirth(D);
     with articulation points, but no bridges.
     <P/>
 
+    <Ref Attr="CutVertices"/> is a synonym for <Ref Attr="ArticulationPoints"/>.
+    <P/>
+
     See also <Ref Prop="IsBiconnectedDigraph"/> and 
     <Ref Prop="IsBridgelessDigraph"/>.
 <Example><![CDATA[

doc/grahom.xml

@@ -563,6 +563,36 @@ gap> DigraphWelshPowellOrder(Digraph([[4], [9], [9], [],
 </ManSection>
 <#/GAPDoc>
 
+<#GAPDoc Label="DigraphSmallestLastOrder">
+<ManSection>
+  <Attr Name="DigraphSmallestLastOrder" Arg="digraph"/>
+  <Returns> A list of vertices.</Returns>
+  <Description>
+    <C>DigraphSmallestLastOrder</C> returns a list <C>order</C> containing each
+    of the vertices of <A>digraph</A> in smallest-last order, defined as
+    follows: <P/>
+
+    Let <M>D_n</M> be <A>digraph</A>. For <M>i = n, n-1, \ldots, 1</M>, the
+    vertex <C>order[i]</C> is a vertex of minimum degree in <M>D_i</M>, and
+    <M>D_{i-1}</M> is the subdigraph of <M>D_i</M> induced by removing
+    <C>order[i]</C>. The degree of a vertex here is the sum of the number of
+    out- and in-neighbours. <P/>
+
+    The result is not unique in general, since there may be several vertices
+    of minimum degree at any step; <C>DigraphSmallestLastOrder</C> tiebreaks
+    by taking the smallest such vertex.
+    <Example><![CDATA[
+gap> D1 := Digraph([[2], [1, 3], [2]]);;
+gap> DigraphSmallestLastOrder(D1);
+[ 3, 2, 1 ]
+gap> D2 := CompleteDigraph(3);;
+gap> DigraphSmallestLastOrder(D2);
+[ 3, 2, 1 ]
+]]></Example>
+  </Description>
+</ManSection>
+<#/GAPDoc>
+
 <#GAPDoc Label="DigraphEmbedding">
 <ManSection>
   <Oper Name="DigraphEmbedding" Arg="digraph1, digraph2"/>

doc/oper.xml

@@ -1957,6 +1957,7 @@ rec( idom := [ 2, fail, 2, 2, 2 ], preorder := [ 2, 1, 3, 4, 5 ] )
 <#GAPDoc Label="IsDigraphOutDominatingSet">
 <ManSection>
   <Oper Name="IsDigraphOutDominatingSet" Arg="digraph, list"/>
+  <Oper Name="IsDigraphDominatingSet" Arg="digraph, list"/>
   <Oper Name="IsDigraphInDominatingSet" Arg="digraph, list"/>
   <Returns><K>true</K> or <K>false</K>.</Returns>
   <Description>
@@ -1973,7 +1974,10 @@ rec( idom := [ 2, fail, 2, 2, 2 ], preorder := [ 2, 1, 3, 4, 5 ] )
     either in <M>S</M> or an out-neighbour of a vertex in <M>S</M>.
     An <E>in-dominating set</E> of <A>digraph</A> is a subset <M>S</M> of
     vertices of <A>digraph</A> such that every vertex of <A>digraph</A> is
-    either in <M>S</M> or an in-neighbour of a vertex in <M>S</M>.
+    either in <M>S</M> or an in-neighbour of a vertex in <M>S</M>. <P/>
+
+    <Ref Oper="IsDigraphDominatingSet"/> is a synonym for
+    <Ref Oper="IsDigraphOutDominatingSet"/>.
 
   <Example><![CDATA[
 gap> D := Digraph([[2, 4], [3], [1, 5], [3], [4]]);;
@@ -2290,6 +2294,7 @@ gap> DigraphDijkstra(D, 1, 2);
 <#GAPDoc Label="ModularProduct">
 <ManSection>
   <Oper Name="ModularProduct" Arg="D1, D2"/>
+  <Oper Name="DigraphModularProduct" Arg="D1, D2"/>
   <Returns>A digraph.</Returns>
   <Description>
   If <A>D1</A> and <A>D2</A> are digraphs without multiple edges, then
@@ -2313,7 +2318,10 @@ gap> DigraphDijkstra(D, 1, 2);
   </List>
 
   Notably, the complete (with loops) subdigraphs of <C>MPD</C> are
-  precisely the partial isomorphisms from <A>D1</A> to <A>D2</A>.
+  precisely the partial isomorphisms from <A>D1</A> to <A>D2</A>. <P/>
+
+  <Ref Oper="DigraphModularProduct"/> is a synonym for
+  <Ref Oper="ModularProduct"/>.
 
   <Example><![CDATA[
 gap> ModularProduct(Digraph([[1], [1, 2]]), Digraph([[], [2]]));
@@ -2333,6 +2341,7 @@ gap> ModularProduct(NullDigraph(0), CompleteDigraph(10));
 <#GAPDoc Label="StrongProduct">
 <ManSection>
   <Oper Name="StrongProduct" Arg="D1, D2"/>
+  <Oper Name="DigraphStrongProduct" Arg="D1, D2"/>
   <Returns>A digraph.</Returns>
   <Description>
   If <A>D1</A> and <A>D2</A> are digraphs without multiple edges,
@@ -2360,7 +2369,10 @@ gap> ModularProduct(NullDigraph(0), CompleteDigraph(10));
   </List>
 
   The SPD of two paths of lengths <C>m</C> and <C>n</C> is also the king's graph
-  for an <C>m</C> by <C>n</C> board. 
+  for an <C>m</C> by <C>n</C> board. <P/>
+
+  <Ref Oper="DigraphStrongProduct"/> is a synonym for
+  <Ref Oper="StrongProduct"/>.
 
   <Example><![CDATA[
 gap> D1 := Digraph([[2], [1, 3, 4], [2, 5], [2, 5], [3, 4]]);
@@ -2380,6 +2392,7 @@ gap> StrongProduct(DigraphSymmetricClosure(ChainDigraph(3)),
 <#GAPDoc Label="ConormalProduct">
 <ManSection>
   <Oper Name="ConormalProduct" Arg="D1, D2"/>
+  <Oper Name="DigraphConormalProduct" Arg="D1, D2"/>
   <Returns>A digraph.</Returns>
   <Description>
   If <A>D1</A> and <A>D2</A> are digraphs without multiple edges,
@@ -2398,7 +2411,10 @@ gap> StrongProduct(DigraphSymmetricClosure(ChainDigraph(3)),
     <Item>
       There is an edge from <C>b</C> to <C>d</C> in <A>D2</A>.
     </Item>
-  </List>
+  </List> <P/>
+
+  <Ref Oper="DigraphConormalProduct"/> is a synonym for
+  <Ref Oper="ConormalProduct"/>.
 
   <Example><![CDATA[
 gap> ConormalProduct(DigraphSymmetricClosure(CycleDigraph(7)),
@@ -2414,6 +2430,7 @@ gap> ConormalProduct(NullDigraph(0), CompleteDigraph(10));
 <#GAPDoc Label="HomomorphicProduct">
 <ManSection>
   <Oper Name="HomomorphicProduct" Arg="D1, D2"/>
+  <Oper Name="DigraphHomomorphicProduct" Arg="D1, D2"/>
   <Returns>A digraph.</Returns>
   <Description>
   If <A>D1</A> and <A>D2</A> are digraphs without multiple edges,
@@ -2433,7 +2450,10 @@ gap> ConormalProduct(NullDigraph(0), CompleteDigraph(10));
       There is an edge from <C>a</C> to <C>c</C> in <A>D1</A> and no edge from
       <C>b</C> to <C>d</C> in <A>D2</A>.
     </Item>
-  </List>
+  </List> <P/>
+
+  <Ref Oper="DigraphHomomorphicProduct"/> is a synonym for
+  <Ref Oper="HomomorphicProduct"/>.
 
   <Example><![CDATA[
 gap> HomomorphicProduct(PetersenGraph(),
@@ -2476,6 +2496,7 @@ gap> OutNeighbours(D1);
 <#GAPDoc Label="LexicographicProduct">
 <ManSection>
   <Oper Name="LexicographicProduct" Arg="D1, D2"/>
+  <Oper Name="DigraphLexicographicProduct" Arg="D1, D2"/>
   <Returns>A digraph.</Returns>
   <Description>
   If <A>D1</A> and <A>D2</A> are digraphs without multiple edges,
@@ -2495,7 +2516,10 @@ gap> OutNeighbours(D1);
       The vertices <C>a</C> and <C>c</C> of <A>D1</A> are equal and there is
       an edge from <C>b</C> to <C>d</C> in <A>D2</A>.
     </Item>
-  </List>
+  </List> <P/>
+
+  <Ref Oper="DigraphLexicographicProduct"/> is a synonym for
+  <Ref Oper="LexicographicProduct"/>.
 
   <Example><![CDATA[
 gap> LexicographicProduct(DigraphSymmetricClosure(CycleDigraph(3)),

doc/prop.xml

@@ -1665,11 +1665,14 @@ false]]></Example>
 <#GAPDoc Label="Is2EdgeTransitive">
 <ManSection>
   <Prop Name="Is2EdgeTransitive" Arg="digraph"/>
+  <Prop Name="IsTwoEdgeTransitive" Arg="digraph"/>
   <Returns><K>true</K> or <K>false</K>.</Returns>
   <Description>
     If <A>digraph</A> is a digraph without multiple edges, then <C>Is2EdgeTransitive</C>
     returns <K>true</K> if <A>digraph</A> is 2-edge transitive, and <K>false</K>
-    otherwise. If <A>digraph</A> has multiple edges, then <C>Is2EdgeTransitive</C> returns an error.
+    otherwise. If <A>digraph</A> has multiple edges, then <C>Is2EdgeTransitive</C> returns an error. <P/>
+
+    <Ref Prop="IsTwoEdgeTransitive"/> is a synonym for <Ref Prop="Is2EdgeTransitive"/>. <P/>
 
     A digraph is <E>2-edge transitive</E> if its automorphism group
     acts transitively on 2-edges via the action

doc/weights.xml

@@ -70,6 +70,36 @@ gap> EdgeWeights(g);
     </ManSection>
 <#/GAPDoc>
 
+<#GAPDoc Label="UnitEdgeWeightedDigraph">
+    <ManSection>
+    <Func Name="UnitEdgeWeightedDigraph" Arg="digraph"/>
+    <Returns>A digraph</Returns>
+    <Description>
+        <!-- TODO update/remove mutability when issue #860 is resolved -->
+        If <A>digraph</A> is immutable, <C>UnitEdgeWeightedDigraph</C> returns
+        an immutable edge-weighted copy of <A>digraph</A>, with all edge weights
+        set to 1. If <A>digraph</A> is mutable, the returned digraph will be
+        mutable, but will not have edge weights. <P/>
+
+        See <Ref Attr="EdgeWeights"/>.
+    <!-- TODO update/remove D2 example when issue #860 is resolved -->
+    <Example><![CDATA[
+gap> D := Digraph([[2], [1, 3], [1]]);
+<immutable digraph with 3 vertices, 4 edges>
+gap> D1 := UnitEdgeWeightedDigraph(D);
+<immutable edge-weighted digraph with 3 vertices, 4 edges>
+gap> EdgeWeights(D1);
+[ [ 1 ], [ 1, 1 ], [ 1 ] ]
+gap> D2 := Digraph(IsMutableDigraph, [[2], [1, 3], [1]]);;
+gap> UnitEdgeWeightedDigraph(D2);
+<mutable digraph with 3 vertices, 4 edges>
+gap> HasEdgeWeights(D2);
+false
+]]></Example>
+    </Description>
+    </ManSection>
+<#/GAPDoc>
+
 <#GAPDoc Label="EdgeWeightedDigraphTotalWeight">
     <ManSection>
     <Attr Name="EdgeWeightedDigraphTotalWeight" Arg="digraph"/>
@@ -91,6 +121,25 @@ gap> EdgeWeightedDigraphTotalWeight(D);
     </ManSection>
 <#/GAPDoc>
 
+<#GAPDoc Label="IsNegativeEdgeWeightedDigraph">
+    <ManSection>
+    <Prop Name="IsNegativeEdgeWeightedDigraph" Arg="digraph"/>
+    <Returns>A boolean.</Returns>
+    <Description>
+        If <A>digraph</A> has edge weights, then this returns <K>true</K> if
+        at least one edge has negative weight, and <K>false</K> otherwise. If
+        <A>digraph</A> has no edge weights, then an error is raised.
+    <Example><![CDATA[
+gap> D := EdgeWeightedDigraph([[2], [1]], [[5], [10]]);;
+gap> IsNegativeEdgeWeightedDigraph(D);
+false
+gap> D := EdgeWeightedDigraph([[2], [1]], [[-5], [10]]);;
+gap> IsNegativeEdgeWeightedDigraph(D);
+true]]></Example>
+    </Description>
+    </ManSection>
+<#/GAPDoc>
+
 <#GAPDoc Label="EdgeWeightedDigraphMinimumSpanningTree">
     <ManSection>
     <Attr Name="EdgeWeightedDigraphMinimumSpanningTree" Arg="digraph"/>

doc/z-chap5.xml

@@ -28,7 +28,9 @@
   <Section><Heading>Edge Weights</Heading>
     <#Include Label="EdgeWeights">
     <#Include Label="EdgeWeightedDigraph">
+    <#Include Label="UnitEdgeWeightedDigraph">
     <#Include Label="EdgeWeightedDigraphTotalWeight">
+    <#Include Label="IsNegativeEdgeWeightedDigraph">
     <#Include Label="EdgeWeightedDigraphMinimumSpanningTree">
     <#Include Label="EdgeWeightedDigraphShortestPaths">
     <#Include Label="EdgeWeightedDigraphShortestPath">

doc/z-chap6.xml

@@ -73,6 +73,7 @@ from} $E_a$ \emph{to} $E_b$. In this case we say that $E_a$ and $E_b$ are
     <#Include Label="DigraphColouring">
     <#Include Label="DigraphGreedyColouring">
     <#Include Label="DigraphWelshPowellOrder">
+    <#Include Label="DigraphSmallestLastOrder">
     <#Include Label="ChromaticNumber">
     <#Include Label="DigraphCore">
     <#Include Label="LatticeDigraphEmbedding">

gap/grahom.gd

@@ -42,7 +42,7 @@ DeclareOperation("DigraphGreedyColouring", [IsDigraph, IsHomogeneousList]);
 DeclareOperation("DigraphGreedyColouringNC", [IsDigraph, IsHomogeneousList]);
 
 DeclareAttribute("DigraphWelshPowellOrder", IsDigraph);
-DeclareAttribute("DigraphSmallestLastOrder", IsDigraph);  # TODO: document
+DeclareAttribute("DigraphSmallestLastOrder", IsDigraph);
 
 DeclareOperation("IsDigraphEndomorphism", [IsDigraph, IsTransformation]);
 DeclareOperation("IsDigraphHomomorphism",

gap/weights.gd

@@ -14,7 +14,7 @@ DeclareGlobalFunction("EdgeWeightedDigraph");
 DeclareProperty("IsNegativeEdgeWeightedDigraph", IsDigraph and HasEdgeWeights);
 DeclareAttribute("EdgeWeightedDigraphTotalWeight",
 IsDigraph and HasEdgeWeights);
-DeclareAttribute("UnitEdgeWeightedDigraph", IsDigraph);
+DeclareOperation("UnitEdgeWeightedDigraph", [IsDigraph]);
 
 # 2. Edge Weight Copies
 DeclareOperation("EdgeWeightsMutableCopy", [IsDigraph and HasEdgeWeights]);